Table of Contents
Advertisement
User Guide
4.1 Management Overview
This section provides an overview of the system management features available in the Ultrastar Data102
through the in-band SAS connections using SG3_utils software, and out-of-band using a REST interface over
HTTPS to access Western Digital's implementation of the DMTF Redfish API.
4.2 Firmware Features Overview
The enclosure services functionality is compatible with the SES-3 (SES3r14) standard. The enclosure
implements the Standalone Enclosure Services Process model described in the SES standard. The logical
enclosure services process is called the SEP. The SEP operates in a dual IOM environment. To a host
server, the SEP exists as a dual ported SAS device, one port on each IOM. The firmware on the Ultrastar
Data102 provides an Active/Active architecture for IOM redundancy. This allows each IOM to independently
report the enclosure status information such as drive power, fan speed, and LED states. This allows the
Ultrastar Data102 to maintain high availability and hot-swappability. Due to the active/active architecture,
commands only need to be executed to one IOM because either IOM is fully capable of performing all
enclosure management tasks. The information and enclosure status will be synchronized between the two
IOMs via the internal SAS links.
The primary expander in each IOM is the only expander that presents a SCSI target, and it is the main device
for gathering information from the system for presentation to hosts. The SEP services SES control page
operations. All control operations follow a synchronous completion model, i.e. the SEP will send SCSI status
only when the requested operation has completed, or to notify the host that the requested operation
cannot be performed. Typical SES control operations include:
• Requesting LED flash patterns
• Recording predicted or known component failures
• Requesting power cycle of one or more drives
• Perform a code download. All firmware in programmable components in the storage subsystem may be
updated via SES.
SES Status
The SEP services SES status pages. All status operations follow a non-blocking completion model, i.e. the
SEP returns the last known status, rather than blocking the completion of the SCSI operation while doing an
immediate polling operation. The SES status is updated every 0.5s. Typical SES status operations include:
• FRU and drive presence, health information, and entity names
• SAS topology maps
• Report sensor readings: temperatures, fan speeds, voltages, currents, etc.
Autonomous Behavior
The SEP autonomously manages enclosure power and thermal characteristics. This is done dynamically
as needed to stay within the allowed operational envelope of power consumption, thermal heating, and
ambient temperature in the data center. This management can include the use of one or more mitigating
actions:
• Raise and lower the cooling fans.
• Enable or disable activity safeguards which limit enclosure activity to reduce power consumption or
heat generation.
• Enter a self-healing thermal offline state in which some or all enclosure components are powered off.
4. Management
4.1 Management Overview
195
Advertisement
Table of Contents
